Adrian Matthias is right -- there is a quotation by Poincare
in his 1908 address describing Cantorian mathematics as
a kind of disease. Surprisingly, the address is easily available
online (in English translation) at:
http://home.att.net/~o.caimi/Poincare.pdf
In Section IX of that address, entitled "Cantorism" he says
(after various negative remarks about Cantorian mathematics):
"I think, and I am not the only one who does, that it is important
never to introduce any conception which may not be
completely defined by a finite number of words.
Whatever may be the remedy adopted, we can promise
ourselves the joy of the physician called in to follow a beautiful
pathological case."